The patients will undergo a baseline magnetic resonance imaging (MRI) as well as a MRI after every six-week cycle to determine response and progression. After 16 patients with recurrent GBM are treated, an interim analysis will be conducted. The most common side effects associated with panitumumab have been dermatological (skin) problems such as erythema (redness of the skin), acneiform rash (skin eruptions of the face), skin exfoliation, pruritus (itching), skin fissures (skin tears), xerosis (dryness of the eye, skin, or mouth), and rash. The most common side effects associated with irinotecan have been decreased blood counts of platelets (increased risk of bleeding), white blood cells (increased risk of infection), red blood cells (anemia); diarrhea, constipation, nausea, vomiting, tiredness, fever, mouth sores, dehydration (excessive loss of body fluids), rash, itching, changes in skin color, swelling, numbness, tingling, dizziness, confusion, low blood pressure, sweating, hot flashes, hair loss, inflammation of the liver, flu-like symptoms, decreased urine output, shortness of breath, and pneumonia (inflammatory disease of the lungs).